1. Field of the Invention
The present invention relates to blowout preventer spanner joints used in the oil and gas industry during subsea well completions.
2. Description of the Related Art
Blowout preventer (BOP) stack spanner joints, commonly referred to as spanners, for a concentric completion or workover well riser have been used to provide well control functions during the installation of a production tubing string in a subsea well. The spanner is included in the tool string immediately above the tubing hanger running tools. The basic functions of the spanner are as follows:
a) The spanner provides a termination for one or more external control umbilical lines and/or hoses. From the point of termination of the control umbilicals at the spanner, the control functions are contained in hydraulic and/or electrical conduits internal to the body of the spanner. PA1 b) The spanner provides a cylindrical outer surface below the termination of the external umbilical which is positioned within the subsea BOP stack in alignment with an annular packoff element which allows closure of the packoff element thereby providing a seal to isolate the well. PA1 c) The spanner provides a transition section between the concentric riser and the parallel bore tubing hanger. The spanner provides communication from the riser annulus to the tubing hanger annulus access bore. The transition section of the spanner includes a wireline tool diverter which allows wireline tools to be lowered through the concentric riser production bore, which is the inner bore, and to enter the annulus access bore. This transition section could also have a remotely operated lever to effect diversion of wireline tools to one bore or the other. PA1 d) The spanner provides valves to allow isolation of the annulus access bore from the production bore and to isolate the riser annulus from the tubing hanger annulus access bore. Both valves are capable of shearing a wireline which could be in the bore when an emergency closure is required. PA1 e) The spanner provides a valve in the production bore to isolate the tubing hanger production bore from the riser production bore. The valve is capable of shearing either a wireline or coiled tubing which could be in the bore when an emergency closure is required.
It is desirable to have a spanner joint assembly having the additional ability to separate the spanner joint assembly in the course of the testing of the well completion equipment. It is also desirable to have the ability in an emergency situation to disconnect the completion/workover riser from the completion equipment leaving the valve portions of the spanner joint assembly connected to the tubing hanger running tools.